1. Field
The disclosed concept pertains generally to trip units and, more particularly, to trip units including a plurality of trip unit settings. The disclosed concept also pertains to circuit breakers including a trip unit.
2. Background Information
Many of today's relatively large circuit breakers include relatively complex electronic trip units that are field replaceable. Often, the number of adjustable settings is sufficiently large such that it is impractical to provide mechanical adjustment of the various settings. The settings are adjusted electronically (e.g., through an operator panel on the trip unit; by an external programming device; remotely through a communication network (e.g., field bus)). In turn, the settings are electronically stored in the trip unit.
When a trip unit fails and, thus, must be replaced, it is often difficult or impossible to determine or retrieve the current settings stored in the failed trip unit. Even if the current settings are known, it is laborious to re-enter those settings in a replacement trip unit.
U.S. Pat. No. 6,005,757 discloses a first or apprentice trip unit interconnected with a second or master trip unit to acquire at least one predetermined setting from the second trip unit. In this manner, there is no requirement to employ some other intelligence, such as that of a user or host computer, to program the first trip unit. Instead, the first trip unit is configured without the substantial involvement of the user and without requiring the presence or expense of a host computer.
There is room for improvement in circuit breakers including a trip unit.
There is also room for improvement in trip units for circuit breakers.